[PATCH v2] libdebugger: Fix for ARMv7-M with -O0 optimization

[chrisj at rtems.org]

From: Chris Johns <chrisj at rtems.org>

---
 cpukit/libdebugger/rtems-debugger-arm.c    | 24 ++++++++++++++++++----
 cpukit/libdebugger/rtems-debugger-server.c |  2 +-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/cpukit/libdebugger/rtems-debugger-arm.c b/cpukit/libdebugger/rtems-debugger-arm.c
index c71af42a02..9e6650886f 100644
--- a/cpukit/libdebugger/rtems-debugger-arm.c
+++ b/cpukit/libdebugger/rtems-debugger-arm.c
@@ -734,7 +734,7 @@ target_exception(CPU_Exception_frame* frame)
  * Note, the code currently assumes cp15 has been set up to match the
  *       instruction set being used.
  */
-#define EXCEPTION_ENTRY_EXC()                                           \
+#define EXCEPTION_ENTRY_EXC_V4()                                        \
   __asm__ volatile(                                                     \
     ASM_ARM_MODE                                                        \
     "sub  sp, %[frame_size]\n"           /* alloc the frame and CPSR */ \
@@ -777,7 +777,7 @@ target_exception(CPU_Exception_frame* frame)
 #define EXCEPTION_ENTRY_FPU(frame_fpu_size)
 #endif /* ARM_MULTILIB_VFP */
 
-#define EXCEPTION_ENTRY_THREAD(_frame)                                  \
+#define EXCEPTION_ENTRY_THREAD_V4(_frame)                               \
   __asm__ volatile(                                                     \
     ASM_ARM_MODE                                                        \
     "ldr  lr, [sp]\n"                        /* recover the link reg */ \
@@ -861,7 +861,7 @@ target_exception(CPU_Exception_frame* frame)
  * Note, the code currently assumes cp15 has been set up to match the
  *       instruction set being used.
  */
-#define EXCEPTION_EXIT_THREAD(_frame)                                   \
+#define EXCEPTION_EXIT_THREAD_V4(_frame)                                \
   __asm__ volatile(                                                     \
     ASM_ARM_MODE                                                        \
     "mov  r0, %[i_frame]\n"                         /* get the frame */ \
@@ -901,7 +901,7 @@ target_exception(CPU_Exception_frame* frame)
       [i_frame] "r" (_frame)                                            \
     : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "memory")
 
-#define EXCEPTION_EXIT_EXC()                                            \
+#define EXCEPTION_EXIT_EXC_V4()                                         \
   __asm__ volatile(                                                     \
     ASM_ARM_MODE                                                        \
     "ldr  lr, [sp]\n"                        /* recover the link reg */ \
@@ -913,6 +913,22 @@ target_exception(CPU_Exception_frame* frame)
     : [frame_size] "i" (EXCEPTION_FRAME_SIZE)                           \
     : "memory")
 
+/**
+ * ARM Variant support.
+ */
+#if defined(ARM_MULTILIB_ARCH_V4)
+ #define EXCEPTION_ENTRY_EXC()               EXCEPTION_ENTRY_EXC_V4()
+ #define EXCEPTION_ENTRY_THREAD(_frame)      EXCEPTION_ENTRY_THREAD_V4(_frame)
+ #define EXCEPTION_EXIT_THREAD(_frame)       EXCEPTION_EXIT_THREAD_V4(_frame)
+ #define EXCEPTION_EXIT_EXC()                EXCEPTION_EXIT_EXC_V4()
+#elif defined(ARM_MULTILIB_ARCH_V7M)
+ #define EXCEPTION_ENTRY_EXC()               (void) arm_switch_reg
+ #define EXCEPTION_ENTRY_THREAD(_frame)      (_frame) = NULL
+ #define EXCEPTION_EXIT_THREAD(_frame)       (_frame) = NULL
+ #define EXCEPTION_EXIT_EXC()                (void) arm_switch_reg
+#else
+ #error ARM architecture is not supported.
+#endif
 
 static void __attribute__((naked))
 target_exception_undefined_instruction(void)
diff --git a/cpukit/libdebugger/rtems-debugger-server.c b/cpukit/libdebugger/rtems-debugger-server.c
index 298bb95989..de841292cb 100644
--- a/cpukit/libdebugger/rtems-debugger-server.c
+++ b/cpukit/libdebugger/rtems-debugger-server.c
@@ -1646,7 +1646,7 @@ remote_packets(uint8_t* buffer, size_t size)
 static void
 rtems_debugger_events(rtems_task_argument arg)
 {
-  int r;
+  int r = 0;
 
   if (rtems_debugger_verbose())
     rtems_debugger_printf("rtems-db: events running\n");
-- 
2.19.1